Ajax应用常见的HTTP ContentType设置

原文出处不详，anyway，感谢一下作者先。

ajax开发中, 常遇到下面的几种情况:

1 服务端需要返回一段普通文本给客户端 
2 服务端需要返回一段HTML代码给客户端 
3 服务端需要返回一段XML代码给客户端 
4 服务端需要返回一段javascript代码给客户端 
5 服务端需要返回一段json串给客户端

对于每一种返回类型，规范的做法是要在服务端指定 response的contentType。
(当然 不指定绝大多数情况下也没什么问题 尤其是返回"非xml"的时候)

代码 
    普通文本 : text/plain
    HTML代码 : text/html
    XML代码 : text/xml
以上三个可以说是毫无争议的, 但是另外两种情况 就要注意一下了. 
javascript 的 contentType 按最标准的写法 应该是 application/javascript. 
而常用的 text/javascript 已经被 rfc定义为废弃的. 
但是，在这里暂时不建议使用 application/javascript
因为很多老旧浏览器并不支持 application/javascript 
而所有浏览器都支持 text/javascript. 
在标准和广泛的兼容性之间 还是暂且选择后者吧.

json 的 contentType 常见写法有: text/json & text/javascript . 
但是 这个 text/json 其实是根本不存在的, 而 text/javascript 在有些时候客户端处理起来会有歧义. 
对于json的contentType , rfc里定义的标准写法是 :application/json.

在这里毫无疑问 我们应该选择标准写法的 application/json

最后，附一下ContentType清单：

常用的：

[java] view plaincopy

1. text/plain
2. text/HTML
3. text/xml
4. test/javascript
5. application/json
6. image/GIF
7. image/JPEG

清单：

[java] view plaincopy

1. ".*"="application/octet-stream"
2. ".001"="application/x-001"
3. ".301"="application/x-301"
4. ".323"="text/h323"
5. ".906"="application/x-906"
6. ".907"="drawing/907"
7. ".a11"="application/x-a11"
8. ".acp"="audio/x-mei-aac"
9. ".ai"="application/postscript"
10. ".aif"="audio/aiff"
11. ".aifc"="audio/aiff"
12. ".aiff"="audio/aiff"
13. ".anv"="application/x-anv"
14. ".asa"="text/asa"
15. ".asf"="video/x-ms-asf"
16. ".asp"="text/asp"
17. ".asx"="video/x-ms-asf"
18. ".au"="audio/basic"
19. ".avi"="video/avi"
20. ".awf"="application/vnd.adobe.workflow"
21. ".biz"="text/xml"
22. ".bmp"="application/x-bmp"
23. ".bot"="application/x-bot"
24. ".c4t"="application/x-c4t"
25. ".c90"="application/x-c90"
26. ".cal"="application/x-cals"
27. ".cat"="application/vnd.ms-pki.seccat"
28. ".cdf"="application/x-netcdf"
29. ".cdr"="application/x-cdr"
30. ".cel"="application/x-cel"
31. ".cer"="application/x-x509-ca-cert"
32. ".cg4"="application/x-g4"
33. ".cgm"="application/x-cgm"
34. ".cit"="application/x-cit"
35. ".class"="java/*"
36. ".cml"="text/xml"
37. ".cmp"="application/x-cmp"
38. ".cmx"="application/x-cmx"
39. ".cot"="application/x-cot"
40. ".crl"="application/pkix-crl"
41. ".crt"="application/x-x509-ca-cert"
42. ".csi"="application/x-csi"
43. ".css"="text/css"
44. ".cut"="application/x-cut"
45. ".dbf"="application/x-dbf"
46. ".dbm"="application/x-dbm"
47. ".dbx"="application/x-dbx"
48. ".dcd"="text/xml"
49. ".dcx"="application/x-dcx"
50. ".der"="application/x-x509-ca-cert"
51. ".dgn"="application/x-dgn"
52. ".dib"="application/x-dib"
53. ".dll"="application/x-msdownload"
54. ".doc"="application/msword"
55. ".dot"="application/msword"
56. ".drw"="application/x-drw"
57. ".dtd"="text/xml"
58. ".dwf"="Model/vnd.dwf"
59. ".dwf"="application/x-dwf"
60. ".dwg"="application/x-dwg"
61. ".dxb"="application/x-dxb"
62. ".dxf"="application/x-dxf"
63. ".edn"="application/vnd.adobe.edn"
64. ".emf"="application/x-emf"
65. ".eml"="message/rfc822"
66. ".ent"="text/xml"
67. ".epi"="application/x-epi"
68. ".eps"="application/x-ps"
69. ".eps"="application/postscript"
70. ".etd"="application/x-ebx"
71. ".exe"="application/x-msdownload"
72. ".fax"="image/fax"
73. ".fdf"="application/vnd.fdf"
74. ".fif"="application/fractals"
75. ".fo"="text/xml"
76. ".frm"="application/x-frm"
77. ".g4"="application/x-g4"
78. ".gbr"="application/x-gbr"
79. ".gcd"="application/x-gcd"
80. ".gif"="image/gif"
81. ".gl2"="application/x-gl2"
82. ".gp4"="application/x-gp4"
83. ".hgl"="application/x-hgl"
84. ".hmr"="application/x-hmr"
85. ".hpg"="application/x-hpgl"
86. ".hpl"="application/x-hpl"
87. ".hqx"="application/mac-binhex40"
88. ".hrf"="application/x-hrf"
89. ".hta"="application/hta"
90. ".htc"="text/x-component"
91. ".htm"="text/html"
92. ".html"="text/html"
93. ".htt"="text/webviewhtml"
94. ".htx"="text/html"
95. ".icb"="application/x-icb"
96. ".ico"="image/x-icon"
97. ".ico"="application/x-ico"
98. ".iff"="application/x-iff"
99. ".ig4"="application/x-g4"
100. ".igs"="application/x-igs"
101. ".iii"="application/x-iphone"
102. ".img"="application/x-img"
103. ".ins"="application/x-internet-signup"
104. ".isp"="application/x-internet-signup"
105. ".IVF"="video/x-ivf"
106. ".java"="java/*"
107. ".jfif"="image/jpeg"
108. ".jpe"="image/jpeg"
109. ".jpe"="application/x-jpe"
110. ".jpeg"="image/jpeg"
111. ".jpg"="image/jpeg"
112. ".jpg"="application/x-jpg"
113. ".js"="application/x-javascript"
114. ".jsp"="text/html"
115. ".la1"="audio/x-liquid-file"
116. ".lar"="application/x-laplayer-reg"
117. ".latex"="application/x-latex"
118. ".lavs"="audio/x-liquid-secure"
119. ".lbm"="application/x-lbm"
120. ".lmsff"="audio/x-la-lms"
121. ".ls"="application/x-javascript"
122. ".ltr"="application/x-ltr"
123. ".m1v"="video/x-mpeg"
124. ".m2v"="video/x-mpeg"
125. ".m3u"="audio/mpegurl"
126. ".m4e"="video/mpeg4"
127. ".mac"="application/x-mac"
128. ".man"="application/x-troff-man"
129. ".math"="text/xml"
130. ".mdb"="application/msaccess"
131. ".mdb"="application/x-mdb"
132. ".mfp"="application/x-shockwave-flash"
133. ".mht"="message/rfc822"
134. ".mhtml"="message/rfc822"
135. ".mi"="application/x-mi"
136. ".mid"="audio/mid"
137. ".midi"="audio/mid"
138. ".mil"="application/x-mil"
139. ".mml"="text/xml"
140. ".mnd"="audio/x-musicnet-download"
141. ".mns"="audio/x-musicnet-stream"
142. ".mocha"="application/x-javascript"
143. ".movie"="video/x-sgi-movie"
144. ".mp1"="audio/mp1"
145. ".mp2"="audio/mp2"
146. ".mp2v"="video/mpeg"
147. ".mp3"="audio/mp3"
148. ".mp4"="video/mpeg4"
149. ".mpa"="video/x-mpg"
150. ".mpd"="application/vnd.ms-project"
151. ".mpe"="video/x-mpeg"
152. ".mpeg"="video/mpg"
153. ".mpg"="video/mpg"
154. ".mpga"="audio/rn-mpeg"
155. ".mpp"="application/vnd.ms-project"
156. ".mps"="video/x-mpeg"
157. ".mpt"="application/vnd.ms-project"
158. ".mpv"="video/mpg"
159. ".mpv2"="video/mpeg"
160. ".mpw"="application/vnd.ms-project"
161. ".mpx"="application/vnd.ms-project"
162. ".mtx"="text/xml"
163. ".mxp"="application/x-mmxp"
164. ".net"="image/pnetvue"
165. ".nrf"="application/x-nrf"
166. ".nws"="message/rfc822"
167. ".odc"="text/x-ms-odc"
168. ".out"="application/x-out"
169. ".p10"="application/pkcs10"
170. ".p12"="application/x-pkcs12"
171. ".p7b"="application/x-pkcs7-certificates"
172. ".p7c"="application/pkcs7-mime"
173. ".p7m"="application/pkcs7-mime"
174. ".p7r"="application/x-pkcs7-certreqresp"
175. ".p7s"="application/pkcs7-signature"
176. ".pc5"="application/x-pc5"
177. ".pci"="application/x-pci"
178. ".pcl"="application/x-pcl"
179. ".pcx"="application/x-pcx"
180. ".pdf"="application/pdf"
181. ".pdf"="application/pdf"
182. ".pdx"="application/vnd.adobe.pdx"
183. ".pfx"="application/x-pkcs12"
184. ".pgl"="application/x-pgl"
185. ".pic"="application/x-pic"
186. ".pko"="application/vnd.ms-pki.pko"
187. ".pl"="application/x-perl"
188. ".plg"="text/html"
189. ".pls"="audio/scpls"
190. ".plt"="application/x-plt"
191. ".png"="image/png"
192. ".png"="application/x-png"
193. ".pot"="application/vnd.ms-powerpoint"
194. ".ppa"="application/vnd.ms-powerpoint"
195. ".ppm"="application/x-ppm"
196. ".pps"="application/vnd.ms-powerpoint"
197. ".ppt"="application/vnd.ms-powerpoint"
198. ".ppt"="application/x-ppt"
199. ".pr"="application/x-pr"
200. ".prf"="application/pics-rules"
201. ".prn"="application/x-prn"
202. ".prt"="application/x-prt"
203. ".ps"="application/x-ps"
204. ".ps"="application/postscript"
205. ".ptn"="application/x-ptn"
206. ".pwz"="application/vnd.ms-powerpoint"
207. ".r3t"="text/vnd.rn-realtext3d"
208. ".ra"="audio/vnd.rn-realaudio"
209. ".ram"="audio/x-pn-realaudio"
210. ".ras"="application/x-ras"
211. ".rat"="application/rat-file"
212. ".rdf"="text/xml"
213. ".rec"="application/vnd.rn-recording"
214. ".red"="application/x-red"
215. ".rgb"="application/x-rgb"
216. ".rjs"="application/vnd.rn-realsystem-rjs"
217. ".rjt"="application/vnd.rn-realsystem-rjt"
218. ".rlc"="application/x-rlc"
219. ".rle"="application/x-rle"
220. ".rm"="application/vnd.rn-realmedia"
221. ".rmf"="application/vnd.adobe.rmf"
222. ".rmi"="audio/mid"
223. ".rmj"="application/vnd.rn-realsystem-rmj"
224. ".rmm"="audio/x-pn-realaudio"
225. ".rmp"="application/vnd.rn-rn_music_package"
226. ".rms"="application/vnd.rn-realmedia-secure"
227. ".rmvb"="application/vnd.rn-realmedia-vbr"
228. ".rmx"="application/vnd.rn-realsystem-rmx"
229. ".rnx"="application/vnd.rn-realplayer"
230. ".rp"="image/vnd.rn-realpix"
231. ".rpm"="audio/x-pn-realaudio-plugin"
232. ".rsml"="application/vnd.rn-rsml"
233. ".rt"="text/vnd.rn-realtext"
234. ".rtf"="application/msword"
235. ".rtf"="application/x-rtf"
236. ".rv"="video/vnd.rn-realvideo"
237. ".sam"="application/x-sam"
238. ".sat"="application/x-sat"
239. ".sdp"="application/sdp"
240. ".sdw"="application/x-sdw"
241. ".sit"="application/x-stuffit"
242. ".slb"="application/x-slb"
243. ".sld"="application/x-sld"
244. ".slk"="drawing/x-slk"
245. ".smi"="application/smil"
246. ".smil"="application/smil"
247. ".smk"="application/x-smk"
248. ".snd"="audio/basic"
249. ".sol"="text/plain"
250. ".sor"="text/plain"
251. ".spc"="application/x-pkcs7-certificates"
252. ".spl"="application/futuresplash"
253. ".spp"="text/xml"
254. ".ssm"="application/streamingmedia"
255. ".sst"="application/vnd.ms-pki.certstore"
256. ".stl"="application/vnd.ms-pki.stl"
257. ".stm"="text/html"
258. ".sty"="application/x-sty"
259. ".svg"="text/xml"
260. ".swf"="application/x-shockwave-flash"
261. ".tdf"="application/x-tdf"
262. ".tg4"="application/x-tg4"
263. ".tga"="application/x-tga"
264. ".tif"="image/tiff"
265. ".tif"="application/x-tif"
266. ".tiff"="image/tiff"
267. ".tld"="text/xml"
268. ".top"="drawing/x-top"
269. ".torrent"="application/x-bittorrent"
270. ".tsd"="text/xml"
271. ".txt"="text/plain"
272. ".uin"="application/x-icq"
273. ".uls"="text/iuls"
274. ".vcf"="text/x-vcard"
275. ".vda"="application/x-vda"
276. ".vdx"="application/vnd.visio"
277. ".vml"="text/xml"
278. ".vpg"="application/x-vpeg005"
279. ".vsd"="application/vnd.visio"
280. ".vsd"="application/x-vsd"
281. ".vss"="application/vnd.visio"
282. ".vst"="application/vnd.visio"
283. ".vst"="application/x-vst"
284. ".vsw"="application/vnd.visio"
285. ".vsx"="application/vnd.visio"
286. ".vtx"="application/vnd.visio"
287. ".vxml"="text/xml"
288. ".wav"="audio/wav"
289. ".wax"="audio/x-ms-wax"
290. ".wb1"="application/x-wb1"
291. ".wb2"="application/x-wb2"
292. ".wb3"="application/x-wb3"
293. ".wbmp"="image/vnd.wap.wbmp"
294. ".wiz"="application/msword"
295. ".wk3"="application/x-wk3"
296. ".wk4"="application/x-wk4"
297. ".wkq"="application/x-wkq"
298. ".wks"="application/x-wks"
299. ".wm"="video/x-ms-wm"
300. ".wma"="audio/x-ms-wma"
301. ".wmd"="application/x-ms-wmd"
302. ".wmf"="application/x-wmf"
303. ".wml"="text/vnd.wap.wml"
304. ".wmv"="video/x-ms-wmv"
305. ".wmx"="video/x-ms-wmx"
306. ".wmz"="application/x-ms-wmz"
307. ".wp6"="application/x-wp6"
308. ".wpd"="application/x-wpd"
309. ".wpg"="application/x-wpg"
310. ".wpl"="application/vnd.ms-wpl"
311. ".wq1"="application/x-wq1"
312. ".wr1"="application/x-wr1"
313. ".wri"="application/x-wri"
314. ".wrk"="application/x-wrk"
315. ".ws"="application/x-ws"
316. ".ws2"="application/x-ws"
317. ".wsc"="text/scriptlet"
318. ".wsdl"="text/xml"
319. ".wvx"="video/x-ms-wvx"
320. ".xdp"="application/vnd.adobe.xdp"
321. ".xdr"="text/xml"
322. ".xfd"="application/vnd.adobe.xfd"
323. ".xfdf"="application/vnd.adobe.xfdf"
324. ".xhtml"="text/html"
325. ".xls"="application/vnd.ms-excel"
326. ".xls"="application/x-xls"
327. ".xlw"="application/x-xlw"
328. ".xml"="text/xml"
329. ".xpl"="audio/scpls"
330. ".xq"="text/xml"
331. ".xql"="text/xml"
332. ".xquery"="text/xml"
333. ".xsd"="text/xml"
334. ".xsl"="text/xml"
335. ".xslt"="text/xml"
336. ".xwd"="application/x-xwd"
337. ".x_b"="application/x-x_b"
338. ".x_t"="application/x-x_t"